Lecture 1 Flashcards
1
Q
What are normal human cells?
A
Diploid, containing 46 chromosomes
2
Q
What do ovaries and testes produce?
A
Haploid gametes
3
Q
Prophase 1
A
- Chromosomes condense and move towards centre
- Nuclear envelope degrades allowing microtubules to attach to kinentochores on chromosome centrioles.
- Chromosomes pair up with homologous partner
4
Q
Metaphase 1
A
- Homologous chromosome pairs line up on metaphase plate
- This is called Reductional division
- The pairs that have different gene alleles line up to be separated
5
Q
Anaphase 1
A
- Chromosomes pulled apart to each cell side
- Only chromosomes are seperated, not individial chromatids
6
Q
Telophase 1
A
- New nuclear envelope forms, two cells form
7
Q
Prophase 2
A
- Same as prophase 1, however microtubules attach to individual chromatids
8
Q
Metaphase 2
A
- Chromosomes line up on metaphase plate
9
Q
Anaphase 2
A
- Sister chromatids seperate and pulled towards centrioles.
- No replication
10
Q
Telophase 2
A
- Cell divides in two
- Result is 4 haploid cells
11
Q
Variation
A
- Independent assortment of chromosomes
- Crossing over
- Random fertilisation
- Mutation
12
Q
Gregor Mendel (years)
A
1822-1884
13
Q
Law of segregation
A
“The two forms of a gene present in each parent segregate independently”
14
Q
Between a homozygous dominant and homozygous reccessive monohybrid cross?
A
- F1 progeny resemble dominant parent
- Both phenotypes show up in F2 (3:1)
- The recessive trait is masked by the dominant (The F1 offspring is known as a “Carrier”, is heterozygous)
15
Q
Test cross
A
- A method for determing individual genotype with dominant phenotype
- Cross it with recessive individual and study offspring
- If homozygous dominant, no recessive phenotype should show
